In a case of contingencies such as disaster like earthquake in urban area, it is desired to promptly perform a rescue request and safety confirmation.
Presently, a lot of people have and always carry a mobile phone. Therefore, it is considered that a rescue request and safety information can be sent from the mobile phone to a disaster center and the like. However, in a case where disaster like earthquake occurs in urban area, a mobile communication channel might not be used due to the destruction of a base station and the like.
Patent literature 1 describes, in a case where disaster strikes, safety confirmation information can be collected from the mobile phones using the satellite communication channel. This makes possible to collect safety confirmation information even when the mobile communication channel cannot be used due to the destruction of the base station and the like.